$.extend($.fn, {

    // https://jqueryvalidation.org/validate/
    validate: function (options) {

        // If nothing is selected, return nothing; can't chain anyway
        if (!this.length) {
            if (options && options.debug && window.console) {
                console.warn("Nothing selected, can't validate, returning nothing.");
            }
            return;
        }

        // Check if a validator for this form was already created
        var validator = $.data(this[0], "validator");
        if (validator) {
            return validator;
        }

        // Add novalidate tag if HTML5.
        this.attr("novalidate", "novalidate");

        validator = new $.validator(options, this[0]);
        $.data(this[0], "validator", validator);

        if (validator.settings.onsubmit) {

            this.on("click.validate", ":submit", function (event) {

                // Track the used submit button to properly handle scripted
                // submits later.
                validator.submitButton = event.currentTarget;

                // Allow suppressing validation by adding a cancel class to the submit button
                if ($(this).hasClass("cancel")) {
                    validator.cancelSubmit = true;
                }

                // Allow suppressing validation by adding the html5 formnovalidate attribute to the submit button
                if ($(this).attr("formnovalidate") !== undefined) {
                    validator.cancelSubmit = true;
                }
            });

            // Validate the form on submit
            this.on("submit.validate", function (event) {
                if (validator.settings.debug) {

                    // Prevent form submit to be able to see console output
                    event.preventDefault();
                }
                function handle() {
                    var hidden, result;

                    // Insert a hidden input as a replacement for the missing submit button
                    // The hidden input is inserted in two cases:
                    //   - A user defined a `submitHandler`
                    //   - There was a pending request due to `remote` method and `stopRequest()`
                    //     was called to submit the form in case it's valid
                    if (validator.submitButton && ( validator.settings.submitHandler || validator.formSubmitted )) {
                        hidden = $("<input type='hidden'/>")
                            .attr("name", validator.submitButton.name)
                            .val($(validator.submitButton).val())
                            .appendTo(validator.currentForm);
                    }

                    if (validator.settings.submitHandler) {
                        result = validator.settings.submitHandler.call(validator, validator.currentForm, event);
                        if (hidden) {

                            // And clean up afterwards; thanks to no-block-scope, hidden can be referenced
                            hidden.remove();
                        }
                        if (result !== undefined) {
                            return result;
                        }
                        return false;
                    }
                    return true;
                }

                // Prevent submit for invalid forms or custom submit handlers
                if (validator.cancelSubmit) {
                    validator.cancelSubmit = false;
                    return handle();
                }
                if (validator.form()) {
                    if (validator.pendingRequest) {
                        validator.formSubmitted = true;
                        return false;
                    }
                    return handle();
                } else {
                    validator.focusInvalid();
                    return false;
                }
            });
        }

        return validator;
    },

    // https://jqueryvalidation.org/valid/
    valid: function () {
        var valid, validator, errorList;

        if ($(this[0]).is("form")) {
            valid = this.validate().form();
        } else {
            errorList = [];
            valid = true;
            validator = $(this[0].form).validate();
            this.each(function () {
                valid = validator.element(this) && valid;
                if (!valid) {
                    errorList = errorList.concat(validator.errorList);
                }
            });
            validator.errorList = errorList;
        }
        return valid;
    },

    // https://jqueryvalidation.org/rules/
    rules: function (command, argument) {
        var element = this[0],
            settings, staticRules, existingRules, data, param, filtered;

        // If nothing is selected, return empty object; can't chain anyway
        if (element == null) {
            return;
        }

        if (!element.form && element.hasAttribute("contenteditable")) {
            element.form = this.closest("form")[0];
            element.name = this.attr("name");
        }

        if (element.form == null) {
            return;
        }

        if (command) {
            settings = $.data(element.form, "validator").settings;
            staticRules = settings.rules;
            existingRules = $.validator.staticRules(element);
            switch (command) {
                case "add":
                    $.extend(existingRules, $.validator.normalizeRule(argument));

                    // Remove messages from rules, but allow them to be set separately
                    delete existingRules.messages;
                    staticRules[element.name] = existingRules;
                    if (argument.messages) {
                        settings.messages[element.name] = $.extend(settings.messages[element.name], argument.messages);
                    }
                    break;
                case "remove":
                    if (!argument) {
                        delete staticRules[element.name];
                        return existingRules;
                    }
                    filtered = {};
                    $.each(argument.split(/\s/), function (index, method) {
                        filtered[method] = existingRules[method];
                        delete existingRules[method];
                    });
                    return filtered;
            }
        }

        data = $.validator.normalizeRules(
            $.extend(
                {},
                $.validator.classRules(element),
                $.validator.attributeRules(element),
                $.validator.dataRules(element),
                $.validator.staticRules(element)
            ), element);

        // Make sure required is at front
        if (data.required) {
            param = data.required;
            delete data.required;
            data = $.extend({required: param}, data);
        }

        // Make sure remote is at back
        if (data.remote) {
            param = data.remote;
            delete data.remote;
            data = $.extend(data, {remote: param});
        }

        return data;
    }
});

// Custom selectors
$.extend($.expr.pseudos || $.expr[":"], {		// '|| $.expr[ ":" ]' here enables backwards compatibility to jQuery 1.7. Can be removed when dropping jQ 1.7.x support

    // https://jqueryvalidation.org/blank-selector/
    blank: function (a) {
        return !$.trim("" + $(a).val());
    },

    // https://jqueryvalidation.org/filled-selector/
    filled: function (a) {
        var val = $(a).val();
        return val !== null && !!$.trim("" + val);
    },

    // https://jqueryvalidation.org/unchecked-selector/
    unchecked: function (a) {
        return !$(a).prop("checked");
    }
});

// Constructor for validator
$.validator = function (options, form) {
    this.settings = $.extend(true, {}, $.validator.defaults, options);
    this.currentForm = form;
    this.init();
};

// https://jqueryvalidation.org/jQuery.validator.format/
$.validator.format = function (source, params) {
    if (arguments.length === 1) {
        return function () {
            var args = $.makeArray(arguments);
            args.unshift(source);
            return $.validator.format.apply(this, args);
        };
    }
    if (params === undefined) {
        return source;
    }
    if (arguments.length > 2 && params.constructor !== Array) {
        params = $.makeArray(arguments).slice(1);
    }
    if (params.constructor !== Array) {
        params = [params];
    }
    $.each(params, function (i, n) {
        source = source.replace(new RegExp("\\{" + i + "\\}", "g"), function () {
            return n;
        });
    });
    return source;
};

$.extend($.validator, {

    defaults: {
        messages: {},
        groups: {},
        rules: {},
        errorClass: "error",
        pendingClass: "pending",
        validClass: "valid",
        errorElement: "label",
        focusCleanup: false,
        focusInvalid: true,
        errorContainer: $([]),
        errorLabelContainer: $([]),
        onsubmit: true,
        ignore: ":hidden",
        ignoreTitle: false,
        onfocusin: function (element) {
            this.lastActive = element;

            // Hide error label and remove error class on focus if enabled
            if (this.settings.focusCleanup) {
                if (this.settings.unhighlight) {
                    this.settings.unhighlight.call(this, element, this.settings.errorClass, this.settings.validClass);
                }
                this.hideThese(this.errorsFor(element));
            }
        },
        onfocusout: function (element) {
            if (!this.checkable(element) && ( element.name in this.submitted || !this.optional(element) )) {
                this.element(element);
            }
        },
        onkeyup: function (element, event) {

            // Avoid revalidate the field when pressing one of the following keys
            // Shift       => 16
            // Ctrl        => 17
            // Alt         => 18
            // Caps lock   => 20
            // End         => 35
            // Home        => 36
            // Left arrow  => 37
            // Up arrow    => 38
            // Right arrow => 39
            // Down arrow  => 40
            // Insert      => 45
            // Num lock    => 144
            // AltGr key   => 225
            var excludedKeys = [
                16, 17, 18, 20, 35, 36, 37,
                38, 39, 40, 45, 144, 225
            ];

            if (event.which === 9 && this.elementValue(element) === "" || $.inArray(event.keyCode, excludedKeys) !== -1) {
                return;
            } else if (element.name in this.submitted || element.name in this.invalid) {
                this.element(element);
            }
        },
        onclick: function (element) {

            // Click on selects, radiobuttons and checkboxes
            if (element.name in this.submitted) {
                this.element(element);

                // Or option elements, check parent select in that case
            } else if (element.parentNode.name in this.submitted) {
                this.element(element.parentNode);
            }
        },
        highlight: function (element, errorClass, validClass) {
            if (element.type === "radio") {
                this.findByName(element.name).addClass(errorClass).removeClass(validClass);
            } else {
                $(element).addClass(errorClass).removeClass(validClass);
            }
        },
        unhighlight: function (element, errorClass, validClass) {
            if (element.type === "radio") {
                this.findByName(element.name).removeClass(errorClass).addClass(validClass);
            } else {
                $(element).removeClass(errorClass).addClass(validClass);
            }
        }
    },

    // https://jqueryvalidation.org/jQuery.validator.setDefaults/
    setDefaults: function (settings) {
        $.extend($.validator.defaults, settings);
    },

    messages: {
        required: "This field is required.",
        remote: "Please fix this field.",
        email: "Please enter a valid email address.",
        url: "Please enter a valid URL.",
        date: "Please enter a valid date.",
        dateISO: "Please enter a valid date (ISO).",
        number: "Please enter a valid number.",
        digits: "Please enter only digits.",
        equalTo: "Please enter the same value again.",
        maxlength: $.validator.format("Please enter no more than {0} characters."),
        minlength: $.validator.format("Please enter at least {0} characters."),
        rangelength: $.validator.format("Please enter a value between {0} and {1} characters long."),
        range: $.validator.format("Please enter a value between {0} and {1}."),
        max: $.validator.format("Please enter a value less than or equal to {0}."),
        min: $.validator.format("Please enter a value greater than or equal to {0}."),
        step: $.validator.format("Please enter a multiple of {0}.")
    },

    autoCreateRanges: false,

    prototype: {

        init: function () {
            this.labelContainer = $(this.settings.errorLabelContainer);
            this.errorContext = this.labelContainer.length && this.labelContainer || $(this.currentForm);
            this.containers = $(this.settings.errorContainer).add(this.settings.errorLabelContainer);
            this.submitted = {};
            this.valueCache = {};
            this.pendingRequest = 0;
            this.pending = {};
            this.invalid = {};
            this.reset();

            var groups = ( this.groups = {} ),
                rules;
            $.each(this.settings.groups, function (key, value) {
                if (typeof value === "string") {
                    value = value.split(/\s/);
                }
                $.each(value, function (index, name) {
                    groups[name] = key;
                });
            });
            rules = this.settings.rules;
            $.each(rules, function (key, value) {
                rules[key] = $.validator.normalizeRule(value);
            });

            function delegate(event) {

                // Set form expando on contenteditable
                if (!this.form && this.hasAttribute("contenteditable")) {
                    this.form = $(this).closest("form")[0];
                    this.name = $(this).attr("name");
                }

                var validator = $.data(this.form, "validator"),
                    eventType = "on" + event.type.replace(/^validate/, ""),
                    settings = validator.settings;
                if (settings[eventType] && !$(this).is(settings.ignore)) {
                    settings[eventType].call(validator, this, event);
                }
            }

            $(this.currentForm)
                .on("focusin.validate focusout.validate keyup.validate",
                    ":text, [type='password'], [type='file'], select, textarea, [type='number'], [type='search'], " +
                    "[type='tel'], [type='url'], [type='email'], [type='datetime'], [type='date'], [type='month'], " +
                    "[type='week'], [type='time'], [type='datetime-local'], [type='range'], [type='color'], " +
                    "[type='radio'], [type='checkbox'], [contenteditable], [type='button']", delegate)

                // Support: Chrome, oldIE
                // "select" is provided as event.target when clicking a option
                .on("click.validate", "select, option, [type='radio'], [type='checkbox']", delegate);

            if (this.settings.invalidHandler) {
                $(this.currentForm).on("invalid-form.validate", this.settings.invalidHandler);
            }
        },

        // https://jqueryvalidation.org/Validator.form/
        form: function () {
            this.checkForm();
            $.extend(this.submitted, this.errorMap);
            this.invalid = $.extend({}, this.errorMap);
            if (!this.valid()) {
                $(this.currentForm).triggerHandler("invalid-form", [this]);
            }
            this.showErrors();
            return this.valid();
        },

        checkForm: function () {
            this.prepareForm();
            for (var i = 0, elements = ( this.currentElements = this.elements() ); elements[i]; i++) {
                this.check(elements[i]);
            }
            return this.valid();
        },

        // https://jqueryvalidation.org/Validator.element/
        element: function (element) {
            var cleanElement = this.clean(element),
                checkElement = this.validationTargetFor(cleanElement),
                v = this,
                result = true,
                rs, group;

            if (checkElement === undefined) {
                delete this.invalid[cleanElement.name];
            } else {
                this.prepareElement(checkElement);
                this.currentElements = $(checkElement);

                // If this element is grouped, then validate all group elements already
                // containing a value
                group = this.groups[checkElement.name];
                if (group) {
                    $.each(this.groups, function (name, testgroup) {
                        if (testgroup === group && name !== checkElement.name) {
                            cleanElement = v.validationTargetFor(v.clean(v.findByName(name)));
                            if (cleanElement && cleanElement.name in v.invalid) {
                                v.currentElements.push(cleanElement);
                                result = v.check(cleanElement) && result;
                            }
                        }
                    });
                }

                rs = this.check(checkElement) !== false;
                result = result && rs;
                if (rs) {
                    this.invalid[checkElement.name] = false;
                } else {
                    this.invalid[checkElement.name] = true;
                }

                if (!this.numberOfInvalids()) {

                    // Hide error containers on last error
                    this.toHide = this.toHide.add(this.containers);
                }
                this.showErrors();

                // Add aria-invalid status for screen readers
                $(element).attr("aria-invalid", !rs);
            }

            return result;
        },

        // https://jqueryvalidation.org/Validator.showErrors/
        showErrors: function (errors) {
            if (errors) {
                var validator = this;

                // Add items to error list and map
                $.extend(this.errorMap, errors);
                this.errorList = $.map(this.errorMap, function (message, name) {
                    return {
                        message: message,
                        element: validator.findByName(name)[0]
                    };
                });

                // Remove items from success list
                this.successList = $.grep(this.successList, function (element) {
                    return !( element.name in errors );
                });
            }
            if (this.settings.showErrors) {
                this.settings.showErrors.call(this, this.errorMap, this.errorList);
            } else {
                this.defaultShowErrors();
            }
        },

        // https://jqueryvalidation.org/Validator.resetForm/
        resetForm: function () {
            if ($.fn.resetForm) {
                $(this.currentForm).resetForm();
            }
            this.invalid = {};
            this.submitted = {};
            this.prepareForm();
            this.hideErrors();
            var elements = this.elements()
                .removeData("previousValue")
                .removeAttr("aria-invalid");

            this.resetElements(elements);
        },

        resetElements: function (elements) {
            var i;

            if (this.settings.unhighlight) {
                for (i = 0; elements[i]; i++) {
                    this.settings.unhighlight.call(this, elements[i],
                        this.settings.errorClass, "");
                    this.findByName(elements[i].name).removeClass(this.settings.validClass);
                }
            } else {
                elements
                    .removeClass(this.settings.errorClass)
                    .removeClass(this.settings.validClass);
            }
        },

        numberOfInvalids: function () {
            return this.objectLength(this.invalid);
        },

        objectLength: function (obj) {
            /* jshint unused: false */
            var count = 0,
                i;
            for (i in obj) {

                // This check allows counting elements with empty error
                // message as invalid elements
                if (obj[i] !== undefined && obj[i] !== null && obj[i] !== false) {
                    count++;
                }
            }
            return count;
        },

        hideErrors: function () {
            this.hideThese(this.toHide);
        },

        hideThese: function (errors) {
            errors.not(this.containers).text("");
            this.addWrapper(errors).hide();
        },

        valid: function () {
            return this.size() === 0;
        },

        size: function () {
            return this.errorList.length;
        },

        focusInvalid: function () {
            if (this.settings.focusInvalid) {
                try {
                    $(this.findLastActive() || this.errorList.length && this.errorList[0].element || [])
                        .filter(":visible")
                        .focus()

                        // Manually trigger focusin event; without it, focusin handler isn't called, findLastActive won't have anything to find
                        .trigger("focusin");
                } catch (e) {

                    // Ignore IE throwing errors when focusing hidden elements
                }
            }
        },

        findLastActive: function () {
            var lastActive = this.lastActive;
            return lastActive && $.grep(this.errorList, function (n) {
                    return n.element.name === lastActive.name;
                }).length === 1 && lastActive;
        },

        elements: function () {
            var validator = this,
                rulesCache = {};

            // Select all valid inputs inside the form (no submit or reset buttons)
            return $(this.currentForm)
                .find("input, select, textarea, [contenteditable]")
                .not(":submit, :reset, :image, :disabled")
                .not(this.settings.ignore)
                .filter(function () {
                    var name = this.name || $(this).attr("name"); // For contenteditable
                    if (!name && validator.settings.debug && window.console) {
                        console.error("%o has no name assigned", this);
                    }

                    // Set form expando on contenteditable
                    if (this.hasAttribute("contenteditable")) {
                        this.form = $(this).closest("form")[0];
                        this.name = name;
                    }

                    // Select only the first element for each name, and only those with rules specified
                    if (name in rulesCache || !validator.objectLength($(this).rules())) {
                        return false;
                    }

                    rulesCache[name] = true;
                    return true;
                });
        },

        clean: function (selector) {
            return $(selector)[0];
        },

        errors: function () {
            var errorClass = this.settings.errorClass.split(" ").join(".");
            return $(this.settings.errorElement + "." + errorClass, this.errorContext);
        },

        resetInternals: function () {
            this.successList = [];
            this.errorList = [];
            this.errorMap = {};
            this.toShow = $([]);
            this.toHide = $([]);
        },

        reset: function () {
            this.resetInternals();
            this.currentElements = $([]);
        },

        prepareForm: function () {
            this.reset();
            this.toHide = this.errors().add(this.containers);
        },

        prepareElement: function (element) {
            this.reset();
            this.toHide = this.errorsFor(element);
        },

        elementValue: function (element) {
            var $element = $(element),
                type = element.type,
                val, idx;

            if (type === "radio" || type === "checkbox") {
                return this.findByName(element.name).filter(":checked").val();
            } else if (type === "number" && typeof element.validity !== "undefined") {
                return element.validity.badInput ? "NaN" : $element.val();
            }

            if (element.hasAttribute("contenteditable")) {
                val = $element.text();
            } else {
                val = $element.val();
            }

            if (type === "file") {

                // Modern browser (chrome & safari)
                if (val.substr(0, 12) === "C:\\fakepath\\") {
                    return val.substr(12);
                }

                // Legacy browsers
                // Unix-based path
                idx = val.lastIndexOf("/");
                if (idx >= 0) {
                    return val.substr(idx + 1);
                }

                // Windows-based path
                idx = val.lastIndexOf("\\");
                if (idx >= 0) {
                    return val.substr(idx + 1);
                }

                // Just the file name
                return val;
            }

            if (typeof val === "string") {
                return val.replace(/\r/g, "");
            }
            return val;
        },

        check: function (element) {
            element = this.validationTargetFor(this.clean(element));

            var rules = $(element).rules(),
                rulesCount = $.map(rules, function (n, i) {
                    return i;
                }).length,
                dependencyMismatch = false,
                val = this.elementValue(element),
                result, method, rule, normalizer;

            // Prioritize the local normalizer defined for this element over the global one
            // if the former exists, otherwise user the global one in case it exists.
            if (typeof rules.normalizer === "function") {
                normalizer = rules.normalizer;
            } else if (typeof this.settings.normalizer === "function") {
                normalizer = this.settings.normalizer;
            }

            // If normalizer is defined, then call it to retreive the changed value instead
            // of using the real one.
            // Note that `this` in the normalizer is `element`.
            if (normalizer) {
                val = normalizer.call(element, val);

                if (typeof val !== "string") {
                    throw new TypeError("The normalizer should return a string value.");
                }

                // Delete the normalizer from rules to avoid treating it as a pre-defined method.
                delete rules.normalizer;
            }

            for (method in rules) {
                rule = {method: method, parameters: rules[method]};
                try {
                    result = $.validator.methods[method].call(this, val, element, rule.parameters);

                    // If a method indicates that the field is optional and therefore valid,
                    // don't mark it as valid when there are no other rules
                    if (result === "dependency-mismatch" && rulesCount === 1) {
                        dependencyMismatch = true;
                        continue;
                    }
                    dependencyMismatch = false;

                    if (result === "pending") {
                        this.toHide = this.toHide.not(this.errorsFor(element));
                        return;
                    }

                    if (!result) {
                        this.formatAndAdd(element, rule);
                        return false;
                    }
                } catch (e) {
                    if (this.settings.debug && window.console) {
                        console.log("Exception occurred when checking element " + element.id + ", check the '" + rule.method + "' method.", e);
                    }
                    if (e instanceof TypeError) {
                        e.message += ".  Exception occurred when checking element " + element.id + ", check the '" + rule.method + "' method.";
                    }

                    throw e;
                }
            }
            if (dependencyMismatch) {
                return;
            }
            if (this.objectLength(rules)) {
                this.successList.push(element);
            }
            return true;
        },

        // Return the custom message for the given element and validation method
        // specified in the element's HTML5 data attribute
        // return the generic message if present and no method specific message is present
        customDataMessage: function (element, method) {
            return $(element).data("msg" + method.charAt(0).toUpperCase() +
                    method.substring(1).toLowerCase()) || $(element).data("msg");
        },

        // Return the custom message for the given element name and validation method
        customMessage: function (name, method) {
            var m = this.settings.messages[name];
            return m && ( m.constructor === String ? m : m[method] );
        },

        // Return the first defined argument, allowing empty strings
        findDefined: function () {
            for (var i = 0; i < arguments.length; i++) {
                if (arguments[i] !== undefined) {
                    return arguments[i];
                }
            }
            return undefined;
        },

        // The second parameter 'rule' used to be a string, and extended to an object literal
        // of the following form:
        // rule = {
        //     method: "method name",
        //     parameters: "the given method parameters"
        // }
        //
        // The old behavior still supported, kept to maintain backward compatibility with
        // old code, and will be removed in the next major release.
        defaultMessage: function (element, rule) {
            if (typeof rule === "string") {
                rule = {method: rule};
            }

            var message = this.findDefined(
                this.customMessage(element.name, rule.method),
                this.customDataMessage(element, rule.method),

                // 'title' is never undefined, so handle empty string as undefined
                    !this.settings.ignoreTitle && element.title || undefined,
                $.validator.messages[rule.method],
                    "<strong>Warning: No message defined for " + element.name + "</strong>"
                ),
                theregex = /\$?\{(\d+)\}/g;
            if (typeof message === "function") {
                message = message.call(this, rule.parameters, element);
            } else if (theregex.test(message)) {
                message = $.validator.format(message.replace(theregex, "{$1}"), rule.parameters);
            }

            return message;
        },

        formatAndAdd: function (element, rule) {
            var message = this.defaultMessage(element, rule);

            this.errorList.push({
                message: message,
                element: element,
                method: rule.method
            });

            this.errorMap[element.name] = message;
            this.submitted[element.name] = message;
        },

        addWrapper: function (toToggle) {
            if (this.settings.wrapper) {
                toToggle = toToggle.add(toToggle.parent(this.settings.wrapper));
            }
            return toToggle;
        },

        defaultShowErrors: function () {
            var i, elements, error;
            for (i = 0; this.errorList[i]; i++) {
                error = this.errorList[i];
                if (this.settings.highlight) {
                    this.settings.highlight.call(this, error.element, this.settings.errorClass, this.settings.validClass);
                }
                this.showLabel(error.element, error.message);
            }
            if (this.errorList.length) {
                this.toShow = this.toShow.add(this.containers);
            }
            if (this.settings.success) {
                for (i = 0; this.successList[i]; i++) {
                    this.showLabel(this.successList[i]);
                }
            }
            if (this.settings.unhighlight) {
                for (i = 0, elements = this.validElements(); elements[i]; i++) {
                    this.settings.unhighlight.call(this, elements[i], this.settings.errorClass, this.settings.validClass);
                }
            }
            this.toHide = this.toHide.not(this.toShow);
            this.hideErrors();
            this.addWrapper(this.toShow).show();
        },

        validElements: function () {
            return this.currentElements.not(this.invalidElements());
        },

        invalidElements: function () {
            return $(this.errorList).map(function () {
                return this.element;
            });
        },

        showLabel: function (element, message) {
            var place, group, errorID, v,
                error = this.errorsFor(element),
                elementID = this.idOrName(element),
                describedBy = $(element).attr("aria-describedby");

            if (error.length) {

                // Refresh error/success class
                error.removeClass(this.settings.validClass).addClass(this.settings.errorClass);

                // Replace message on existing label
                error.html(message);
            } else {

                // Create error element
                error = $("<" + this.settings.errorElement + ">")
                    .attr("id", elementID + "-error")
                    .addClass(this.settings.errorClass)
                    .html(message || "");

                // Maintain reference to the element to be placed into the DOM
                place = error;
                if (this.settings.wrapper) {

                    // Make sure the element is visible, even in IE
                    // actually showing the wrapped element is handled elsewhere
                    place = error.hide().show().wrap("<" + this.settings.wrapper + "/>").parent();
                }
                if (this.labelContainer.length) {
                    this.labelContainer.append(place);
                } else if (this.settings.errorPlacement) {
                    this.settings.errorPlacement.call(this, place, $(element));
                } else {
                    place.insertAfter(element);
                }

                // Link error back to the element
                if (error.is("label")) {

                    // If the error is a label, then associate using 'for'
                    error.attr("for", elementID);

                    // If the element is not a child of an associated label, then it's necessary
                    // to explicitly apply aria-describedby
                } else if (error.parents("label[for='" + this.escapeCssMeta(elementID) + "']").length === 0) {
                    errorID = error.attr("id");

                    // Respect existing non-error aria-describedby
                    if (!describedBy) {
                        describedBy = errorID;
                    } else if (!describedBy.match(new RegExp("\\b" + this.escapeCssMeta(errorID) + "\\b"))) {

                        // Add to end of list if not already present
                        describedBy += " " + errorID;
                    }
                    $(element).attr("aria-describedby", describedBy);

                    // If this element is grouped, then assign to all elements in the same group
                    group = this.groups[element.name];
                    if (group) {
                        v = this;
                        $.each(v.groups, function (name, testgroup) {
                            if (testgroup === group) {
                                $("[name='" + v.escapeCssMeta(name) + "']", v.currentForm)
                                    .attr("aria-describedby", error.attr("id"));
                            }
                        });
                    }
                }
            }
            if (!message && this.settings.success) {
                error.text("");
                if (typeof this.settings.success === "string") {
                    error.addClass(this.settings.success);
                } else {
                    this.settings.success(error, element);
                }
            }
            this.toShow = this.toShow.add(error);
        },

        errorsFor: function (element) {
            var name = this.escapeCssMeta(this.idOrName(element)),
                describer = $(element).attr("aria-describedby"),
                selector = "label[for='" + name + "'], label[for='" + name + "'] *";

            // 'aria-describedby' should directly reference the error element
            if (describer) {
                selector = selector + ", #" + this.escapeCssMeta(describer)
                        .replace(/\s+/g, ", #");
            }

            return this
                .errors()
                .filter(selector);
        },

        // See https://api.jquery.com/category/selectors/, for CSS
        // meta-characters that should be escaped in order to be used with JQuery
        // as a literal part of a name/id or any selector.
        escapeCssMeta: function (string) {
            return string.replace(/([\\!"#$%&'()*+,./:;<=>?@\[\]^`{|}~])/g, "\\$1");
        },

        idOrName: function (element) {
            return this.groups[element.name] || ( this.checkable(element) ? element.name : element.id || element.name );
        },

        validationTargetFor: function (element) {

            // If radio/checkbox, validate first element in group instead
            if (this.checkable(element)) {
                element = this.findByName(element.name);
            }

            // Always apply ignore filter
            return $(element).not(this.settings.ignore)[0];
        },

        checkable: function (element) {
            return ( /radio|checkbox/i ).test(element.type);
        },

        findByName: function (name) {
            return $(this.currentForm).find("[name='" + this.escapeCssMeta(name) + "']");
        },

        getLength: function (value, element) {
            switch (element.nodeName.toLowerCase()) {
                case "select":
                    return $("option:selected", element).length;
                case "input":
                    if (this.checkable(element)) {
                        return this.findByName(element.name).filter(":checked").length;
                    }
            }
            return value.length;
        },

        depend: function (param, element) {
            return this.dependTypes[typeof param] ? this.dependTypes[typeof param](param, element) : true;
        },

        dependTypes: {
            "boolean": function (param) {
                return param;
            },
            "string": function (param, element) {
                return !!$(param, element.form).length;
            },
            "function": function (param, element) {
                return param(element);
            }
        },

        optional: function (element) {
            var val = this.elementValue(element);
            return !$.validator.methods.required.call(this, val, element) && "dependency-mismatch";
        },

        startRequest: function (element) {
            if (!this.pending[element.name]) {
                this.pendingRequest++;
                $(element).addClass(this.settings.pendingClass);
                this.pending[element.name] = true;
            }
        },

        stopRequest: function (element, valid) {
            this.pendingRequest--;

            // Sometimes synchronization fails, make sure pendingRequest is never < 0
            if (this.pendingRequest < 0) {
                this.pendingRequest = 0;
            }
            delete this.pending[element.name];
            $(element).removeClass(this.settings.pendingClass);
            if (valid && this.pendingRequest === 0 && this.formSubmitted && this.form()) {
                $(this.currentForm).submit();

                // Remove the hidden input that was used as a replacement for the
                // missing submit button. The hidden input is added by `handle()`
                // to ensure that the value of the used submit button is passed on
                // for scripted submits triggered by this method
                if (this.submitButton) {
                    $("input:hidden[name='" + this.submitButton.name + "']", this.currentForm).remove();
                }

                this.formSubmitted = false;
            } else if (!valid && this.pendingRequest === 0 && this.formSubmitted) {
                $(this.currentForm).triggerHandler("invalid-form", [this]);
                this.formSubmitted = false;
            }
        },

        previousValue: function (element, method) {
            method = typeof method === "string" && method || "remote";

            return $.data(element, "previousValue") || $.data(element, "previousValue", {
                    old: null,
                    valid: true,
                    message: this.defaultMessage(element, {method: method})
                });
        },

        // Cleans up all forms and elements, removes validator-specific events
        destroy: function () {
            this.resetForm();

            $(this.currentForm)
                .off(".validate")
                .removeData("validator")
                .find(".validate-equalTo-blur")
                .off(".validate-equalTo")
                .removeClass("validate-equalTo-blur");
        }

    },

    classRuleSettings: {
        required: {required: true},
        email: {email: true},
        url: {url: true},
        date: {date: true},
        dateISO: {dateISO: true},
        number: {number: true},
        digits: {digits: true},
        creditcard: {creditcard: true}
    },

    addClassRules: function (className, rules) {
        if (className.constructor === String) {
            this.classRuleSettings[className] = rules;
        } else {
            $.extend(this.classRuleSettings, className);
        }
    },

    classRules: function (element) {
        var rules = {},
            classes = $(element).attr("class");

        if (classes) {
            $.each(classes.split(" "), function () {
                if (this in $.validator.classRuleSettings) {
                    $.extend(rules, $.validator.classRuleSettings[this]);
                }
            });
        }
        return rules;
    },

    normalizeAttributeRule: function (rules, type, method, value) {

        // Convert the value to a number for number inputs, and for text for backwards compability
        // allows type="date" and others to be compared as strings
        if (/min|max|step/.test(method) && ( type === null || /number|range|text/.test(type) )) {
            value = Number(value);

            // Support Opera Mini, which returns NaN for undefined minlength
            if (isNaN(value)) {
                value = undefined;
            }
        }

        if (value || value === 0) {
            rules[method] = value;
        } else if (type === method && type !== "range") {

            // Exception: the jquery validate 'range' method
            // does not test for the html5 'range' type
            rules[method] = true;
        }
    },

    attributeRules: function (element) {
        var rules = {},
            $element = $(element),
            type = element.getAttribute("type"),
            method, value;

        for (method in $.validator.methods) {

            // Support for <input required> in both html5 and older browsers
            if (method === "required") {
                value = element.getAttribute(method);

                // Some browsers return an empty string for the required attribute
                // and non-HTML5 browsers might have required="" markup
                if (value === "") {
                    value = true;
                }

                // Force non-HTML5 browsers to return bool
                value = !!value;
            } else {
                value = $element.attr(method);
            }

            this.normalizeAttributeRule(rules, type, method, value);
        }

        // 'maxlength' may be returned as -1, 2147483647 ( IE ) and 524288 ( safari ) for text inputs
        if (rules.maxlength && /-1|2147483647|524288/.test(rules.maxlength)) {
            delete rules.maxlength;
        }

        return rules;
    },

    dataRules: function (element) {
        var rules = {},
            $element = $(element),
            type = element.getAttribute("type"),
            method, value;

        for (method in $.validator.methods) {
            value = $element.data("rule" + method.charAt(0).toUpperCase() + method.substring(1).toLowerCase());
            this.normalizeAttributeRule(rules, type, method, value);
        }
        return rules;
    },

    staticRules: function (element) {
        var rules = {},
            validator = $.data(element.form, "validator");

        if (validator.settings.rules) {
            rules = $.validator.normalizeRule(validator.settings.rules[element.name]) || {};
        }
        return rules;
    },

    normalizeRules: function (rules, element) {

        // Handle dependency check
        $.each(rules, function (prop, val) {

            // Ignore rule when param is explicitly false, eg. required:false
            if (val === false) {
                delete rules[prop];
                return;
            }
            if (val.param || val.depends) {
                var keepRule = true;
                switch (typeof val.depends) {
                    case "string":
                        keepRule = !!$(val.depends, element.form).length;
                        break;
                    case "function":
                        keepRule = val.depends.call(element, element);
                        break;
                }
                if (keepRule) {
                    rules[prop] = val.param !== undefined ? val.param : true;
                } else {
                    $.data(element.form, "validator").resetElements($(element));
                    delete rules[prop];
                }
            }
        });

        // Evaluate parameters
        $.each(rules, function (rule, parameter) {
            rules[rule] = $.isFunction(parameter) && rule !== "normalizer" ? parameter(element) : parameter;
        });

        // Clean number parameters
        $.each(["minlength", "maxlength"], function () {
            if (rules[this]) {
                rules[this] = Number(rules[this]);
            }
        });
        $.each(["rangelength", "range"], function () {
            var parts;
            if (rules[this]) {
                if ($.isArray(rules[this])) {
                    rules[this] = [Number(rules[this][0]), Number(rules[this][1])];
                } else if (typeof rules[this] === "string") {
                    parts = rules[this].replace(/[\[\]]/g, "").split(/[\s,]+/);
                    rules[this] = [Number(parts[0]), Number(parts[1])];
                }
            }
        });

        if ($.validator.autoCreateRanges) {

            // Auto-create ranges
            if (rules.min != null && rules.max != null) {
                rules.range = [rules.min, rules.max];
                delete rules.min;
                delete rules.max;
            }
            if (rules.minlength != null && rules.maxlength != null) {
                rules.rangelength = [rules.minlength, rules.maxlength];
                delete rules.minlength;
                delete rules.maxlength;
            }
        }

        return rules;
    },

    // Converts a simple string to a {string: true} rule, e.g., "required" to {required:true}
    normalizeRule: function (data) {
        if (typeof data === "string") {
            var transformed = {};
            $.each(data.split(/\s/), function () {
                transformed[this] = true;
            });
            data = transformed;
        }
        return data;
    },

    // https://jqueryvalidation.org/jQuery.validator.addMethod/
    addMethod: function (name, method, message) {
        $.validator.methods[name] = method;
        $.validator.messages[name] = message !== undefined ? message : $.validator.messages[name];
        if (method.length < 3) {
            $.validator.addClassRules(name, $.validator.normalizeRule(name));
        }
    },

    // https://jqueryvalidation.org/jQuery.validator.methods/
    methods: {

        // https://jqueryvalidation.org/required-method/
        required: function (value, element, param) {

            // Check if dependency is met
            if (!this.depend(param, element)) {
                return "dependency-mismatch";
            }
            if (element.nodeName.toLowerCase() === "select") {

                // Could be an array for select-multiple or a string, both are fine this way
                var val = $(element).val();
                return val && val.length > 0;
            }
            if (this.checkable(element)) {
                return this.getLength(value, element) > 0;
            }
            return value.length > 0;
        },

        // https://jqueryvalidation.org/email-method/
        email: function (value, element) {

            // From https://html.spec.whatwg.org/multipage/forms.html#valid-e-mail-address
            // Retrieved 2014-01-14
            // If you have a problem with this implementation, report a bug against the above spec
            // Or use custom methods to implement your own email validation
            return this.optional(element) || /^[a-zA-Z0-9.!#$%&'*+\/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$/.test(value);
        },

        // https://jqueryvalidation.org/url-method/
        url: function (value, element) {

            // Copyright (c) 2010-2013 Diego Perini, MIT licensed
            // https://gist.github.com/dperini/729294
            // see also https://mathiasbynens.be/demo/url-regex
            // modified to allow protocol-relative URLs
            return this.optional(element) || /^(?:(?:(?:https?|ftp):)?\/\/)(?:\S+(?::\S*)?@)?(?:(?!(?:10|127)(?:\.\d{1,3}){3})(?!(?:169\.254|192\.168)(?:\.\d{1,3}){2})(?!172\.(?:1[6-9]|2\d|3[0-1])(?:\.\d{1,3}){2})(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)(?:\.(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)*(?:\.(?:[a-z\u00a1-\uffff]{2,})).?)(?::\d{2,5})?(?:[/?#]\S*)?$/i.test(value);
        },

        // https://jqueryvalidation.org/date-method/
        date: function (value, element) {
            return this.optional(element) || !/Invalid|NaN/.test(new Date(value).toString());
        },

        // https://jqueryvalidation.org/dateISO-method/
        dateISO: function (value, element) {
            return this.optional(element) || /^\d{4}[\/\-](0?[1-9]|1[012])[\/\-](0?[1-9]|[12][0-9]|3[01])$/.test(value);
        },

        // https://jqueryvalidation.org/number-method/
        number: function (value, element) {
            return this.optional(element) || /^(?:-?\d+|-?\d{1,3}(?:,\d{3})+)?(?:\.\d+)?$/.test(value);
        },

        // https://jqueryvalidation.org/digits-method/
        digits: function (value, element) {
            return this.optional(element) || /^\d+$/.test(value);
        },

        // https://jqueryvalidation.org/minlength-method/
        minlength: function (value, element, param) {
            var length = $.isArray(value) ? value.length : this.getLength(value, element);
            return this.optional(element) || length >= param;
        },

        // https://jqueryvalidation.org/maxlength-method/
        maxlength: function (value, element, param) {
            var length = $.isArray(value) ? value.length : this.getLength(value, element);
            return this.optional(element) || length <= param;
        },

        // https://jqueryvalidation.org/rangelength-method/
        rangelength: function (value, element, param) {
            var length = $.isArray(value) ? value.length : this.getLength(value, element);
            return this.optional(element) || ( length >= param[0] && length <= param[1] );
        },

        // https://jqueryvalidation.org/min-method/
        min: function (value, element, param) {
            return this.optional(element) || value >= param;
        },

        // https://jqueryvalidation.org/max-method/
        max: function (value, element, param) {
            return this.optional(element) || value <= param;
        },

        // https://jqueryvalidation.org/range-method/
        range: function (value, element, param) {
            return this.optional(element) || ( value >= param[0] && value <= param[1] );
        },

        // https://jqueryvalidation.org/step-method/
        step: function (value, element, param) {
            var type = $(element).attr("type"),
                errorMessage = "Step attribute on input type " + type + " is not supported.",
                supportedTypes = ["text", "number", "range"],
                re = new RegExp("\\b" + type + "\\b"),
                notSupported = type && !re.test(supportedTypes.join()),
                decimalPlaces = function (num) {
                    var match = ( "" + num ).match(/(?:\.(\d+))?$/);
                    if (!match) {
                        return 0;
                    }

                    // Number of digits right of decimal point.
                    return match[1] ? match[1].length : 0;
                },
                toInt = function (num) {
                    return Math.round(num * Math.pow(10, decimals));
                },
                valid = true,
                decimals;

            // Works only for text, number and range input types
            // TODO find a way to support input types date, datetime, datetime-local, month, time and week
            if (notSupported) {
                throw new Error(errorMessage);
            }

            decimals = decimalPlaces(param);

            // Value can't have too many decimals
            if (decimalPlaces(value) > decimals || toInt(value) % toInt(param) !== 0) {
                valid = false;
            }

            return this.optional(element) || valid;
        },

        // https://jqueryvalidation.org/equalTo-method/
        equalTo: function (value, element, param) {

            // Bind to the blur event of the target in order to revalidate whenever the target field is updated
            var target = $(param);
            if (this.settings.onfocusout && target.not(".validate-equalTo-blur").length) {
                target.addClass("validate-equalTo-blur").on("blur.validate-equalTo", function () {
                    $(element).valid();
                });
            }
            return value === target.val();
        },

        // https://jqueryvalidation.org/remote-method/
        remote: function (value, element, param, method) {
            if (this.optional(element)) {
                return "dependency-mismatch";
            }

            method = typeof method === "string" && method || "remote";

            var previous = this.previousValue(element, method),
                validator, data, optionDataString;

            if (!this.settings.messages[element.name]) {
                this.settings.messages[element.name] = {};
            }
            previous.originalMessage = previous.originalMessage || this.settings.messages[element.name][method];
            this.settings.messages[element.name][method] = previous.message;

            param = typeof param === "string" && {url: param} || param;
            optionDataString = $.param($.extend({data: value}, param.data));
            if (previous.old === optionDataString) {
                return previous.valid;
            }

            previous.old = optionDataString;
            validator = this;
            this.startRequest(element);
            data = {};
            data[element.name] = value;
            $.ajax($.extend(true, {
                mode: "abort",
                port: "validate" + element.name,
                dataType: "json",
                data: data,
                context: validator.currentForm,
                success: function (response) {
                    var valid = response === true || response === "true",
                        errors, message, submitted;

                    validator.settings.messages[element.name][method] = previous.originalMessage;
                    if (valid) {
                        submitted = validator.formSubmitted;
                        validator.resetInternals();
                        validator.toHide = validator.errorsFor(element);
                        validator.formSubmitted = submitted;
                        validator.successList.push(element);
                        validator.invalid[element.name] = false;
                        validator.showErrors();
                    } else {
                        errors = {};
                        message = response || validator.defaultMessage(element, {method: method, parameters: value});
                        errors[element.name] = previous.message = message;
                        validator.invalid[element.name] = true;
                        validator.showErrors(errors);
                    }
                    previous.valid = valid;
                    validator.stopRequest(element, valid);
                }
            }, param));
            return "pending";
        }
    }

});
